To monitor the function of a kidney transplant, your doctors check your creatinine levels. Creatinine is a good measure of the function of kidney transplants, but this blood test does not give a complete picture of how well the kidney is doing.

A biopsy of the kidney provides much more information than your blood tests. A biopsy tells the doctor what is happening at the microscopic level in your kidney. A biopsy can identify early scarring that can happen with chronic rejection, injury to the kidney from medications, or silent rejection that sometimes can occur without causing the creatinine to go up. Sometimes problems can go on for a long time before the creatinine rises, so biopsy findings can help your doctor make the best decisions for your treatment. For example, silent rejection can be treated with a short course of extra anti-rejection drugs.

Your doctor will order a transplant biopsy at three and twelve months after transplant. At the same time, we also obtain blood tests to check for a virus called BK virus that can damage kidneys, and do blood tests that tells us how suppressed your immune system is. This evaluation is a like a “regular maintenance check” to be sure that your kidney is functioning as well as possible.

The biopsy is performed with a special needle that removes two tiny pieces of kidney guided by ultrasound pictures. It takes about a half hour to perform this outpatient procedure, and only lidocaine (local) anesthetic is required. After the procedure, you will rest in bed for four hours and then return home. Afterward, you must avoid lifting heavy objects or doing deep bends for one week. You can then return to normal activity.

Before it is time for your biopsy, one of the transplant doctors will talk to you during a clinic visit in more detail and prepare you for the procedure with instructions and an appointment. About two to three weeks after the biopsy, you will have another clinic visit to discuss in detail the results of the biopsy and the blood tests and to make any changes in antirejection therapy that may be needed.